Osteoporosis is a systemic disorder characterized by decreased bone mass and microarchitectural deterioration of bone tissue leading to bone fragility and increased susceptibility to fractures of hip, spine, and wrist. Osteopenia has been defined as the appearance of decreased bone mineral content on radiography, but the term more appropriately refers to a phase in the continuum from decreased bone mass to fractures and infirmity. By the time the diagnosis of osteopenia is made radiographically, significant and irreversible bone loss has already occurred. The most common cause of osteopenia is osteoporosis; other causes include osteomalacia and the bone disease of hyperparathyroidism.
In the United States, roughly 1 in 4 women over the age of 50 has osteoporosis. The overall prevalence of osteoporotic fractures rises dramatically in menopausal women. Bone loss is more abrupt for the first decade after the onset of menopause, followed by more gradual loss thereafter (Nordin, et al., “How can we prevent osteoporosis?” in Osteoporosis, Christiansen, et al., (eds). Copenhagen, Norhaven A/S, 1204-1210 (1987)). With increasing age, fracture incidence increases. The frequency of hip fractures increases exponentially with age, particularly after age 70, and is more commonly seen in white women. About 32% of women who live to age 80 have hip fractures (Gallagher, et al., Clin. Orthop. 150:163-171 (1980); Melton, et al., Am. J. Epidemiol. 129:1000-1011 (1989)). A woman's risk of a hip fracture equals the combined risk of breast, uterine, and ovarian cancer, and the risk of dying of hip fracture is equal to breast cancer mortality (Elffors, Aging (Milano) 10:191-204 (1998)). The prevalence of vertebral fractures is 42% in women of advanced age and/or who have decreased bone mass (Melton et al., 1989). In women, a rapid rise of vertebral fractures, which is initially associated with the onset of menopause, is followed by an increase in the frequency of wrist and hip fractures due to age-related bone loss.
Osteoporosis develops less often in men than women because bone loss starts later and progresses more slowly in men, and there is no period of rapid hormonal change and accompanying rapid bone loss. Differences in bone geometry and remodeling also contribute to the lower rate of fractures in men. However, in the past few years, the problem of osteoporosis in men has become recognized as an important public health issue, particularly in light of estimates that the number of men older than 70 will double between 1993 and 2050 according to the US National Osteoporosis Foundation.
Roughly 1 in 8 men over the age of 50 years has osteoporosis. Presently, more than 2 million men in the United States are affected by osteoporosis, and another 3 million are at risk for this disease. Each year, men have one third of all hip fractures that occur, and one third of these men will not survive more than a year. The frequency of hip fracture increases exponentially with age, particularly after age 70, and 17% of men who live to age 80 have hip fractures (Gallagher et al., 1980; Melton et al., 1989). In addition to hip fracture, men also have painful and debilitating fractures of the spine, wrist, and other bones due to osteoporosis.
While the damages caused by osteoporosis are severe and are sometimes fatal, no exact clinical chemical tests on blood or urine are abnormal in osteoporosis. Currently used techniques are generally biochemical markers, radiography, and measurement of bone mineral density (BMD). The use of these techniques is limited either by cost or by accuracy reasons.
It is an object of the present invention to provide an effective means for evaluation of environmental and bone infectious stresses on the skeletal system.
It is a further object of the present invention to provide a means for treating and/or preventing infectious disorders having a negative impact on the skeletal system.